NERVE-ENDINGS. 353 



and is doubtless susceptible of still wider applications. The 

 process used by him is given below, 714. 



670. Nerve-endings other Methods. 



BEEMER (Arch. f. mik. Anat., 1882, p. 195). Impregnate according to 

 the method of Fischer, ante, 224, and soak for two or three weeks in 

 glycerin containing 20 per cent, of formic acid. Mount in glycerin contain- 

 ing 1 per cent, of formic acid. 



CIACCIO (Joum. de Micrographie, 1883, p. 38). Lemon'juice followed 

 by 1 per cent, solution of double chloride of gold and cadmium, and reduc- 

 tion partly in the light and partly in concentrated formic acid in the dark. 



WOLFF (Arch. f. mik. Anat., 1881, p. 355). Study of the living muscle 

 in salt solution. 



GAEL SACHS (ibid.}. Dilute acetic acid followed by very weak picric acid 

 for twenty-four hours. After mounting in glycerin, this gives very trans- 

 parent preparations. 



KEAUSE (Intern. Monatschr. f. Anat. u. Hist. ; Zeit. f. wiss. Mik., 1885, 

 p. 547). A muscle is put for three or four hours into concentrated solution 

 of oxalic acid, then boiled for two minutes in water, treated for twenty-four 

 hours with O'l per cent, osmic acid, and mounted in glycerin. 



NEGEO (Zeit.f. wiss. Mik., v, 2, 1888, p. 240). Make the following solu- 

 tion : 



Concentrated solution of ammonia alum . . 180 parts. 

 Griibler's saturated alcoholic solution of hsema- 



toxylin ........ 2 ,, 



Mix, and let the mixture stand for a week exposed to the air, and add 25 

 c.c. each of methyl alcohol and glycerin. A drop of this is brought on to a 

 fresh preparation of muscle of Tropidonotus natrix, Lacerta viridis, or 

 Rana, and in a few minutes the stain is washed out and the preparation 

 mounted in balsam. 



BOCCAEDI (see Zeit. f. wiss. Mik., iv, 4, 1887, p. 492). Preparations 

 treated according to Ranvier's lemon-juice method or his formic acid method 

 are washed in distilled water, and put for a couple of hours into oxalic acid 

 of from O'l to 0'25 or 0'30 per cent., or, better, into a mixture of 

 Pure formic acid ....... 5 c.c. 



1 per cent, oxalic acid 1 



Distilled water 25 



Then washed and mounted in glycerin. 



KUHNE (Zeit.f. Biol., xxiii, v, 1887, p. 1 ; Zeit.f. wiss. Mik., iv, 4, 1887, 

 p. 495). This paper contains a critical review of the different gold methods, 

 of which the following are the principal conclusions : 



(1) The method of Lowit is particularly applicable to thin entire (un- 

 teased) muscles. , 



(2) Preliminary treatment with weak (0'5 per cent.) formic acid, and re- 

 duction in dilute glycerin containing one-fourth to one-fifth volume of 

 formic acid, in the dark, is a good process for muscles of warm-blooded 

 animals. 



23 



